An embodiment of the present invention relates to a medical image diagnostic apparatus and a medical image processing apparatus which are used for paracentesis.
In the medical field, a medical image of an imaging region in an object (patient) is noninvasively acquired by using a medical image diagnostic apparatus such as an ultrasonic diagnostic apparatus, X-ray computed tomography apparatus, magnetic resonance imaging apparatus, X-ray diagnostic apparatus, or nuclear medicine diagnostic apparatus. For example, ultrasonic diagnosis enables real-time display of how the heart beats or the fetus moves, by simply bringing an ultrasonic probe into contact with the body surface. This technique is also highly safe, and hence allows repeated examination. Furthermore, this system is smaller in size than other diagnostic apparatuses such as X-ray, CT, and MRI apparatuses and can be moved to the bedside to be easily and conveniently used for examination. In addition, ultrasonic diagnosis is free from the influences of exposure using X-rays and the like, and hence can be used in obstetric treatment, treatment at home, and the like.
In general, the frame rate of an ultrasonic diagnostic apparatus is 30 Hz or more. A major feature of this apparatus is that it enables the real-time observation of the dynamic behavior of an organ or blood flow. By using this feature, the ultrasonic diagnostic apparatus is also frequently used for the guidance of a puncture needle. A puncture needle is used for the collection of a tissue sample (biopsy) and has recently been used for paracentesis such as a needle ablation treatment of emitting microwaves or radiowaves from the needle tip. The operator can monitor, in real time, how the needle reaches a treatment region such as a tumor, via an ultrasonic image obtained by using an ultrasonic diagnostic image.
There are several problems in monitoring using ultrasonic images in paracentesis. For example, an ultrasonic diagnostic apparatus is generally designed to acquire two-dimensional tomographic images. For this reason, the range which can be simultaneously visualized in ultrasonic diagnosis is narrower than in an X-ray computed tomography apparatus and a magnetic resonance imaging apparatus. This makes it impossible to accurately record the position of a puncture needle by using a two-dimensional ultrasonic image when the tip of the puncture needle falls outside an ultrasonic scan plane. Recently, an ultrasonic diagnostic apparatus capable of real-time three-dimensional scanning has been developed. This can prevent the needle tip from falling outside a scan volume. Even the use of three-dimensional scanning does not lead to a fundamental solution to problems such as inability to recognize the needle tip position when a high-echo region and the needle overlap.
Under the circumstances, there has recently been proposed a technique of simultaneously displaying, in real time, an ultrasonic tomographic image and a CT tomographic image or MR tomographic image at the same position by attaching a position sensor or the like using magnetism to the probe of an ultrasonic diagnostic apparatus and aligning separately acquired CT volume data (volume data acquired by an X-ray computed tomography apparatus) or MR volume data (volume data acquired by a magnetic resonance imaging apparatus) with the ultrasonic tomographic image. There has also been developed a tool which allows a position sensor to be attached to a needle itself which performs a puncture treatment. Using this tool makes it possible to acquire the relative position between the ultrasonic probe and the needle tip in real time by using the position sensor. In this case, the needle tip can be displayed on an ultrasonic tomographic image while, for example, being highlighted or changed in color tone. These techniques also allow the needle tip position of a puncture needle to be displayed on, for example, CT volume data in real time.
Each conventional apparatus used in paracentesis, however, has a room for improvement from the viewpoint of improving the objectivity of a puncture result, that is, recording the puncture result as an evidence, while sufficiently guaranteeing safety at the time of puncture. For example, strong demands have arisen, in consideration of an improvement in medical quality as well, for the development of an evidence function in a case of inserting a plurality of puncture needles, a function concerning the review of a puncture result, and a function of feeding back a puncture result for effective utilization.
In consideration of the above situation, it is an object to provide a medical image diagnostic apparatus and a medical image processing apparatus which calculate the needle tip position of a puncture needle on volume data used for monitoring at a predetermined timing during paracentesis, store paracentesis information including at least the needle tip position and volume data used for monitoring in association with each other, and can posteriorly reproduce the data.